1. Field of the Invention
This invention generally relates to Armor Penetrating, Fin Stabilized Discarding Sabot (APFSDS) Kinetic Energy (KE) projectile cartridges and more particularly to pre-molded seal sleeves designed to prevent gas intrusion into a projectile assembly.
2. Description of Related Art
Current configurations for 105 mm and 120 mm APFSDS KE tank ammunition cartridges typically include a projectile assembly centrally located within a case.
The ammunition cartridge basically includes a tubular case having a closed head end and an open mouth end. The projectile assembly extends into and is secured to the case mouth end. During assembly of the cartridge, a propellant is loaded into the cavity between the case and the projectile assembly.
The projectile assembly includes a long rod shaped penetrator which has a pointed front tip and a fin assembly attached to the rear of the penetrator. The penetrator is encircled by a sabot assembly which has three sabot segments spaced from each other 120.degree.. Each sabot segment has a front bourrelet portion, a rearwardly tapered central portion, an aft bourrelet, and a tapered rear portion. Each sabot segment has two flat radial faces which extend axially from front to rear. The segments are joined with faces abutting one another around the penetrator to form the full bore sabot.
The propellant for firing the projectile creates copious amounts of heat and gas during combustion. Without protection, the projectile assembly may be damaged by the heat and gas. Accordingly, an aft seal is provided to prevent gas and heat intrusion into the projectile assembly. Aft seal sleeves are conventionally formed of silicone rubber or room temperature vulcanized (RTV) rubber and formed by in-place molding over the tapered rear portion of the sabot after the projectile is placed in the casing.
A conventional APFSDS KE weapon using a rubber or an RTV seal is disclosed in U.S. Pat. No. 5,183,961 to Campoli et al. which is herein incorporated by reference in its entirety.
The Campoli et al. patent discloses a rubber or an RTV rubber seal manufactured by in-place injection molding of RTV rubber into a mold cap which is placed on the projectile aft ramp. The required mold tooling and process operations generally make this manufacturing technique time-consuming and expensive.
During ballistic test firings of saboted projectiles, the propellant typically tears or gouges the RTV rubber seals provided to protect the projectile during the propellant burn process. A damaged RTV rubber seal allows gases to penetrate the projectile assembly and either damage the projectile or reduce its ballistic performance.
Additionally, RTV rubber does not bond especially well to the sabot material. A properly prepared surface of an aluminum sabot may provide a good bonding surface for the RTV rubber, but requires additional processing steps that add cost. Moreover, new configurations of large caliber ammunition include sabots of high strength composite materials. Typically, these composite materials provide poor bonding capability for RTV rubber that may lead to poor performance because of projectile damage.
Accordingly, a seal is needed which eliminates problems associated with the RTV rubber seal. There is also needed a seal that can be easily tailored to specific requirements by modifying component blend ratios.
There is also needed a seal that can then be bonded to a sabot using an adhesive which is selected based on its capability to bond to both the sabot and the seal.
There is also needed a seal that can be manufactured and installed at reduced costs when compared to the current RTV rubber process of molding the seal in-place.
Finally, there is also needed a seal to reduce the overall projectile weight when compared to the current RTV rubber shield configuration.